Set a bit in ProviderMethodsModule to see if we are generating provider methods for gin.  If we are, skip fast class generation.
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=71452336
Merge pull request #823 from google/moe_writing_branch_from_5b65f8c4dcf95a89d3b5ace2dbee3e54fa963722

Merge internal changes -- removes a warning from Gin.